Internal Processes

Question 1

Divergent boundary

Answer 1

1) Magma rises between two plates –> going away from each other
2) EITHER midocean ridge OR continental rift

Question 2

Convergent boundary

Answer 2

1) plates colliding, destructive boundaries
2) lead to orogenesis (mountain building)
3) 3 types: oceanic-continental, oceanic-oceanic, continental-continental

Question 3

Oceanic-continental convergence

Answer 3

1) Oceanic plate goes into asthenosphere of continental
2) Features: creates oceanic trench + volcanic mountains on continental crust

Question 4

Oceanic-Oceanic Convergence

Answer 4

1) More dense oceanic crust subducts
2) Water involved –> cool magma, produces felsic
3) Key Features = oceanic trench, volcanic arc

Question 5

Continental Continental Convergence

Answer 5

1) No subduction because continental crust too buoyant
2) creates huge mountain ranges like himalayas

Question 6

Transform boundaries

Answer 6

1) plates slide laterally –> no new crust created or old crust destroyed
2) found in midocean ridges + in California

Question 7

Two additions to plate tectonic theory

Answer 7

1) hot spots
2) accreted terranes

Question 8

Hot Spots

Answer 8

1) Explains the formation of volcanic islands and seamount chains away from tectonic plate boundaries.
2) A hotspot is a stationary mantle plume that creates volcanic activity as tectonic plates move over it, creating a chain

Question 9

Accreted terrane

Answer 9

1) Fragment of crustal material added to a tectonic plate, found at convergent plate boundaries.
2) explains why plate can have very different sections w. diff geologic features

Question 10

Volcanic Distribution

Answer 10

1) found in areas of convergence
2) Ring of Fire (andesite line)
3) considered active if erupted once within historical times + likely to erupt again

Question 11

benefits of volcanoes

Answer 11

1) most of water on earth today released as water vapor during volcanic eruptions
2) magma contains phosphorus, K, Ca, Mg

Question 12

4 types of volcanoes

Answer 12

Shield, composite/strato, cinder cone, lava dome

Question 13

Shield volcanoes

Answer 13

1) broad + gently sloping mountain, much broader than tall
2) made of layers of solidified lava flows
3) basaltic magma + fluid lava

Question 14

Composite volcano

Answer 14

1) steep sided symmetrical cone
2) made of layers of lava, pyroclastics (ash/cinder), hardened volcanic mudflow
3) explosive + effusive eruptions
4) more felsic + viscous –> makes explosive

Question 15

Lava Dome (Plug Dome)

Answer 15

1) small, irregular shape
2) made of solidified lava that was thick/viscous when molten
3) magma high in silica, explosive eruptions

Question 16

Cinder Cone

Answer 16

1) small, steep-sided cone
2) loose pyroclastics (ash/cinder)
3) baslatic magma, short life span
4) extremely explosive

Question 17

Caldera

Answer 17

immense basin-shaped depression (circular) with diameter much larger than volcano vent forms post eruption
ex: crater lake

Question 18

Volcanic Hazards

Answer 18

1) Volcanic gases = sudden release of carbon dioxide + sulfur dioxide dangerous –> lead to acid rain + reduce insolation
2) lava flows –> not that dangerous BUT lava flows from intermediate/high silica magma dangerous because explosive
3) eruption column - large fragments of rock - called volcanic bombs - drop to ground + lots of ash falls
4) pyroclastic flow - high speed avalanche of searing hot gases, ash, rock
5) volcanic mudflows - caused when hot ash mixes with water/melting snow –> produces slurry of mud/boulders

Question 19

Types of folding

Answer 19

1) Anticline
2) Syncline

Question 20

Anticline

Answer 20

1) symmetrical upfold - creates mountains
2) Sad face parabolas

Question 21

syncline

Answer 21

1) symmetrical downfold - creates valleys
2) Happy face parabola

Question 22

Two types of tectonism

Answer 22

1) folding = crustal rocks become deformed because of lateral compression
2) faulting = rock structure is broken + one is forcibly displaced by other

Question 23

Types of faults

Answer 23

1) Normal faults
2) reverse fault
3) thrust faults
4) strike-slip

Question 24

Earthquake

Answer 24

1) vibration in Earth produced by shock waves caused from sudden displacement along fault

Question 25

Earthquake dangers

Answer 25

1) Ground shaking –> liquefaction + breaking of buildings
2) landslides
3) tsunami = if underwater earthquake

Question 26

Hanging wall vs footwall

Answer 26

1) Hanging wall = plate that is moving (on right)
2) footwall = plate the stays still (on left)

Question 27

Normal Fault

Answer 27

1) Normal faults = (GOING APART) tension stresses (pulling apart) –> produces steeply inclined fault zone

Question 28

Reverse Fault

Answer 28

1) reverse fault = (COMING TOGETHER) compression stresses (pushing together), one block slides UP incline
2) hanging wall pushed up

Question 29

Thrust Fault (don’t need to know)

Answer 29

1) thrust faults = Earth’s crust where one piece of rock is pushed up and over another at shallow angle (less than 30 degrees)

Question 30

Strike Slip Fault

Answer 30

1) strike-slip = lateral movement